Backpack



FIG. 1 is a back side perspective view of a backpack with case attached showing my new design;

FIG. 2 is a front side perspective view thereof;

FIG. 3 is a back side elevation view of the backpack with case detached;

FIG. 4 is a front side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a right side elevation view thereof;

FIG. 7 is a top side plan view thereof; and,

FIG. 8 is a bottom side plan view thereof.

The broken lines in the figures are for the purpose of illustrating portions of the backpack and form no part of the claim. 

CLAIM The ornamental design for a backpack, as shown and described. 